Abstract: The 4 MeV raphytron consists of an X-ray head,a controller,a modulator cabinet,a cooling water cabinet and a motorized positioning system (option). The raphytron 4MeV is capable of producing useful X-ray beams with characteristics usually used in high energy industrial radiography techniques. The major performance of raphytron 4MeV are as follows:Electron beam energy: 4MeV; X-ray dose rete:≥3. 50 Gy/min (on the central axis);X-ray field size: Φ 400 mm(at one meter) X-ray focal spot size: Φ 2 mmaX-ray flatness:>70% of the central axis intensity (at: ±7.5° of the central axis, no X-ray beam filter); X-ray unsymmetry: <±2% (at ±7. 5° of the central axis) Detection range:for steel, thickness of 50—250mm Radiographic quality : equivalently 1—2T level as defined in ASME E142.